New Hot Runners for Small and Large Parts

A handful of hot-runner developments were announced by Mold-Masters Ltd., Georgetown, Ont., at the recent K 2004 show in Dusseldorf.

A handful of hot-runner developments were announced by Mold-Masters Ltd., Georgetown, Ont., at the recent K 2004 show in Dusseldorf. First, the Femto-Lite line of small hot-runner nozzles comes in a new size of 11 mm diam., which permits pitches as tight as 19 mm, and standard lengths from 73 to 163 mm.


At the other end of the scale, Mold-Masters announced four new components in its Flex-Series for large parts. One is the XXL compact, modular hot half with separate cooling circuits in each plate. It is shipped fully assembled and ready for mounting on the cavity plate. Second, a new “3-in-one/slide” nozzle is built of three standard components (including replaceable heater) instead of the usual one-piece design. The nozzle flange slides along the back of the manifold to compensate for heat expansion. This allows use in large manifolds without bridge construction.


Third, the new HY7800 hydraulic unit for valve-gate actuation is compact to minimize stack height. The system is separately cooled and has integral valve-pin alignment. Pins are mounted without opening the oil chamber and tips can be adjusted ±1.5 mm from outside the manifold. Fourth, a new manifold heating system, which is replaceable on-site, uses special heaters fused to the top and bottom of the manifold. All cables are stored in a cable duct.


In addition the company added two new space-saving, lower-priced controllers to its TempMaster line. Model XL-II costs up to 30% less because it controls two zones per data card, so up to 18 zones can now fit in a cabinet that previously held nine zones. Second, the new MZ-LT controller is a smaller, more economical version of its heavy-duty MZ line. It can control up to 60 zones with hot-swappable cards. Users can view color graphs, drawings and photographs on its display. Both units require no calibration or maintenance.


Mold-Masters also discussed several developments that are approaching commercialization. Its new Melt-Disk technology provides multiple horizontal hot tips from one nozzle for side-gating of four to eight pipettes, syringe barrels, and needle lids. The design is said to eliminate cold slugs. Also, a new gating method speeds color changes by up to 50%. Its symmetrical, pressure-balanced design reportedly ensures rapid and complete wash-out of the first color. Versions for tip or valve gates are being designed. Mold-Masters is also developing a new melt-transfer technology for stack molds that eliminates drooling and stringing. It eliminates the sprue bar to keep the parting line clear. This Stack-Link technology has a completely self-sealing shut-off of the melt channel when the mold opens.